Y
X Z
tan Y = XZ / XY = 3/2 ⇒ XZ = (3/2)XY
Therefore, by Pythagoras
XY^2 + XZ^2 = 80^2
XY^2 + [ (3/2) XY ] ^2 = 6400
XY^2 + (9/4)XY^2 = 6400
(13/4)XY^2 = 6400
XY^2 = 6400 / (13/4)
XY^2 = 6400 * 4 / 13
XY = sqrt [ (6400 * 4 ) / 13 ] = 160 / sqrt 13 ≈ 44.38
